Wierd Oil Pressure?
Wierd Oil Pressure? Like the tile says, I'm getting some wierd things happening with my oil pressure. First off, my oil pressure ranges from 25psi @ idle to 70psi @ ~6k rpm at operating temperature. Secondly, when I'm accelerating at WOT my oil pressure gets up to about 60psi at ~4k rpm, starts to drop off to ~45-50psi then goes back up between 5k and 6k rpm. I have a melling hi pressure pump that I installed when I rebuilt the engine, I believe it is a M55? Has anyone else had a similar problem?
I probably should mention that I am running Mobil Delvac 15w-40.
I probably should mention that I am running Mobil Delvac 15w-40.
Yes, the windage try is installed. I was thinking that the pump could be starved for oil, but I would think that would happen toward the bottom of the rpms as that is where the most G-force is made
yea, the pan is stock. Will an aftermarket pan fit with a stock k-member?
That is one problem that i considered when planning the engine, which is why I went with a high pressure pump, rather than a high volume pump. The engine builder I talked to said that a high volume pump would suck the pan dry, whereas a high pressure pump would still retain the the same call for volume as a stock pump. As I understood it, all the high pressure pump is, is a different spring put into the pump to keep it from bleeding off the extra pressure too early, correct me if I'm wrong
That is one problem that i considered when planning the engine, which is why I went with a high pressure pump, rather than a high volume pump. The engine builder I talked to said that a high volume pump would suck the pan dry, whereas a high pressure pump would still retain the the same call for volume as a stock pump. As I understood it, all the high pressure pump is, is a different spring put into the pump to keep it from bleeding off the extra pressure too early, correct me if I'm wrong
Last edited by ryle; Feb 6, 2009 at 05:34 PM.
also Sprayed, if that were the case, why would my pressure shortly after the dip, raise up close to 70PSI. if the pan were sucked dry, how would it be able to regain that pressure?
I have the same problem you have. I just bought a canton pan to try and stop this problem as a last resort. Some things that could cause this you that should be checked is;
Pickup height
Relief valve sticking in the pump
Oil pump drive under the manifold.
Over filled oil
None of those was the cure for me but it doesn't mean it cant be for you.
Here is a thread i started a while back on my issue. https://ls1tech.com/forums/advanced-...ure-issue.html
Pickup height
Relief valve sticking in the pump
Oil pump drive under the manifold.
Over filled oil
None of those was the cure for me but it doesn't mean it cant be for you.
Here is a thread i started a while back on my issue. https://ls1tech.com/forums/advanced-...ure-issue.html
Last edited by Jditlfm; Feb 6, 2009 at 08:18 PM.
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Brett Foote As it sits right now, I believe it is that the pickup is too close to the pan. When the builder mocked up the pickup, he put the pickup on the pump so that is was a little too high, then placed a pan on over it to push it down. Then took the pan off and welded the pickup in place. my guess is that the pickup is pretty much touching the pan.
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From: Decatur, TN (N-W of Athens)
I believe the high volume pumps are the one that drain our stock pans, but the high pressure doesn't. This is TOTALLY speculation and I'm only saying this to see what others think, so don't start to panic: What if that certain RPM was spinning just right for bearings that were just slightly mis-installed, so it wasn't lining up with the oil holes enough? :\
Or your sensor is just acting weird and there's some electrical signal/harmonics being produced that makes the gauge mis-read during that RPM.
Or your sensor is just acting weird and there's some electrical signal/harmonics being produced that makes the gauge mis-read during that RPM.
Honestly, I really don't have any experience diagnosing this sort of problem; it was merely a suggestion.
I believe the high volume pumps are the one that drain our stock pans, but the high pressure doesn't. This is TOTALLY speculation and I'm only saying this to see what others think, so don't start to panic: What if that certain RPM was spinning just right for bearings that were just slightly mis-installed, so it wasn't lining up with the oil holes enough? :\
Or your sensor is just acting weird and there's some electrical signal/harmonics being produced that makes the gauge mis-read during that RPM.
Or your sensor is just acting weird and there's some electrical signal/harmonics being produced that makes the gauge mis-read during that RPM.
TECH Senior Member
iTrader: (3)
Joined: Oct 2006
Posts: 7,564
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From: Decatur, TN (N-W of Athens)
Maybe hook up another gauge at a different location for the oil? I know on 93s, our sensor is down by the filter, where as the rest are up behind the intake like most other GM V8s. If your filter housing has the provision for a sensor but has a plug, maybe toss in an electrical one, or another mechanical spigot to re-route the gauge to. Otherwise I'd say maybe try different weight oil.
heh I'm just really chucking out anything I can think of.
